Storage arrays, traditionally monolithic entities running firmware on a storage controller and managing input/output (I/O) to disks, are incorporating virtualization. With the advent of cloud computing, a paradigm shift is taking place in the storage industry. Cloud computing is a model for enabling on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. While most of the focus on cloud computing is related to the infrastructure and software delivery/usage models, the concept of multi tenancy is gaining interest from a storage perspective. In an Infrastructure as a Service (IaaS) model, the storage infrastructure (i.e. array controller(s) and groups of disks) would be leveraged across multiple clients. Multi tenancy requires that data and configuration be partitioned within the storage array with an assurance that operations being performed in one of the tenants does not flow-in or be visible to any other tenant. These multi-tenancy requirements cannot be met by basic LUN mapping/partitioning.
As an example, two hosts (e.g., competing companies) may require storage provisioning from a storage infrastructure service. Carving out two different logical units on the same array would not serve the interests of the two hosts for at least two reasons. First, there is the risk of an invalid operation executed from one of the hosts in the configuration bringing down/incapacitating the entire array and hence hampering accessibility from other clients. Second, the hosts which requested the provisioned storage infrastructure may be wary of having their I/O's handled by the same instance of controller firmware that could potentially be handling I/O's for their competitors simultaneously and hence could inadvertently lead to data mismanagement. The traditional solution to this problem would be to configure two different storage arrays, provision storage space on them and allow the LUN mappings to the required hosts. As is evident, such a setup is not scalable, nor can such a setup meet the challenging demands of the cloud world.